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File:  [LON-CAPA] / loncom / types / Queue.pm
Revision 1.4: download - view: text, annotated - select for diffs
Thu Apr 24 15:12:40 2003 UTC (21 years ago) by albertel
Branches: MAIN
CVS tags: version_2_9_X, version_2_9_99_0, version_2_9_1, version_2_9_0, version_2_8_X, version_2_8_99_1, version_2_8_99_0, version_2_8_2, version_2_8_1, version_2_8_0, version_2_7_X, version_2_7_99_1, version_2_7_99_0, version_2_7_1, version_2_7_0, version_2_6_X, version_2_6_99_1, version_2_6_99_0, version_2_6_3, version_2_6_2, version_2_6_1, version_2_6_0, version_2_5_X, version_2_5_99_1, version_2_5_99_0, version_2_5_2, version_2_5_1, version_2_5_0, version_2_4_X, version_2_4_99_0, version_2_4_2, version_2_4_1, version_2_4_0, version_2_3_X, version_2_3_99_0, version_2_3_2, version_2_3_1, version_2_3_0, version_2_2_X, version_2_2_99_1, version_2_2_99_0, version_2_2_2, version_2_2_1, version_2_2_0, version_2_1_X, version_2_1_99_3, version_2_1_99_2, version_2_1_99_1, version_2_1_99_0, version_2_1_3, version_2_1_2, version_2_1_1, version_2_1_0, version_2_12_X, version_2_11_X, version_2_11_4_uiuc, version_2_11_4_msu, version_2_11_4, version_2_11_3_uiuc, version_2_11_3_msu, version_2_11_3, version_2_11_2_uiuc, version_2_11_2_msu, version_2_11_2_educog, version_2_11_2, version_2_11_1, version_2_11_0_RC3, version_2_11_0_RC2, version_2_11_0_RC1, version_2_11_0, version_2_10_X, version_2_10_1, version_2_10_0_RC2, version_2_10_0_RC1, version_2_10_0, version_2_0_X, version_2_0_99_1, version_2_0_2, version_2_0_1, version_2_0_0, version_1_99_3, version_1_99_2, version_1_99_1_tmcc, version_1_99_1, version_1_99_0_tmcc, version_1_99_0, version_1_3_X, version_1_3_3, version_1_3_2, version_1_3_1, version_1_3_0, version_1_2_X, version_1_2_99_1, version_1_2_99_0, version_1_2_1, version_1_2_0, version_1_1_X, version_1_1_99_5, version_1_1_99_4, version_1_1_99_3, version_1_1_99_2, version_1_1_99_1, version_1_1_99_0, version_1_1_3, version_1_1_2, version_1_1_1, version_1_1_0, version_1_0_99_3, version_1_0_99_2, version_1_0_99_1, version_1_0_99, version_1_0_3, version_1_0_2, version_1_0_1, version_1_0_0, version_0_99_5, version_0_99_4, version_0_99_3, version_0_99_2, version_0_99_1, version_0_99_0, loncapaMITrelate_1, language_hyphenation_merge, language_hyphenation, conference_2003, bz6209-base, bz6209, bz5969, bz2851, PRINT_INCOMPLETE_base, PRINT_INCOMPLETE, HEAD, GCI_3, GCI_2, GCI_1, BZ5971-printing-apage, BZ5434-fox, BZ4492-merge, BZ4492-feature_horizontal_radioresponse
- fixing pod

    1: #  Implement a simple queue in terms of a list.
    2: #
    3: # $Id: Queue.pm,v 1.4 2003/04/24 15:12:40 albertel Exp $
    4: #
    5: # Copyright Michigan State University Board of Trustees
    6: #
    7: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
    8: #
    9: # LON-CAPA is free software; you can redistribute it and/or modify
   10: # it under the terms of the GNU General Public License as published by
   11: # the Free Software Foundation; either version 2 of the License, or
   12: # (at your option) any later version.
   13: #
   14: # LON-CAPA is distributed in the hope that it will be useful,
   15: # but WITHOUT ANY WARRANTY; without even the implied warranty of
   16: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   17: # GNU General Public License for more details.
   18: #
   19: # You should have received a copy of the GNU General Public License
   20: # along with LON-CAPA; if not, write to the Free Software
   21: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   22: #
   23: # /home/httpd/html/adm/gpl.txt
   24: #
   25: # http://www.lon-capa.org/
   26: #
   27: 
   28: =pod
   29: 
   30: =head1 Queue
   31: 
   32: An object oriented implementation of a queue data structure.  queues
   33: are first in last out data structures.
   34: 
   35: =head1 Member functions:
   36: 
   37: =cut
   38: 
   39: package Queue;
   40: 
   41: 
   42: =pod
   43: 
   44: =head2 new 
   45: 
   46:   Construct a new queue.
   47: 
   48: =cut
   49: 
   50: sub new {
   51:     my $class = shift;		# Class name to bless into.
   52:     my $self  = [];		# Our data is a reference to an anon. array.
   53: 
   54:     bless($self, $class);	# Type this as an object.
   55: 
   56:     return $self;
   57: }
   58: 
   59: =pod
   60: 
   61: =head2 enqueue
   62: 
   63:    Add an element to the tail of the queue.
   64: 
   65: =cut
   66: 
   67: sub enqueue {
   68:     my $self = shift;		# Get object reference.
   69:     my $item = shift;		# Get the item to enqueue...
   70:     push(@$self, $item);		# Push the item to the back of the array.
   71: 
   72: 
   73: }
   74: 
   75: =pod
   76: 
   77: =head2 dequeue
   78: 
   79:    Remove an element from the front of the queue.
   80: 
   81: =cut
   82: 
   83: sub dequeue {
   84:     my $self = shift;		# Get object reference....
   85:     return shift @$self;		# Remove from the front of the queue.
   86: }
   87: 
   88: 
   89: =pod  
   90: 
   91: =head1 Count
   92: 
   93: Returns number of items in a queue.
   94: 
   95: =cut
   96: 
   97: sub Count {
   98:     my $self = shift;
   99:     my $count = scalar(@$self);
  100:     return $count;
  101: }
  102: 
  103: 1;
  104: 
  105: =pod
  106: 
  107: =head1 Theory
  108: 
  109: The queue is implemented as an array... enqueue is a thinly disguised
  110: push, and dequeue is a thinly disguised shift.  This is probably quite
  111: in efficient for large queues, but should be fine for reasonably sized
  112: queues.
  113: 
  114: Note that since Perl is a dynamically typed language, queues can
  115: contain objects of any data type and can even be heterogenously typed.
  116: 
  117: =cut
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